The 1950s conflict ended in a truce, leaving North and South Korea without a formal peace treaty. The North now says it might return to six-party nuclear talks if its demands are met.

Reporting from Tokyo — Fifty-seven years after the end of the bloody Korean conflict, always unpredictable North Korea on Monday proposed a peace treaty to formally end the hostilities.

The communist state suggested that once a treaty was underway, it would return to the stalled six-party talks to end the regime's nuclear ambitions. But first, North Korean officials say, they want international sanctions imposed last year to be lifted immediately.

The proposal was met with skepticism from the U.S. and its allies, including South Korea.

The 1950-53 conflict on the Korean peninsula ended in a truce, not a treaty, a detail that technically has left the region at war. But North Korea indicated it would like to change that stalemate with a formal treaty, suggesting that it would sign the document and return to the six-party talks.

North Korea abandoned the talks, which included the United States, Russia, China, Japan and South Korea, last year in protest over international sanctions imposed after it tested a long-range missile. Kim Jong Il, the regime's leader, wants the United Nations to end the economic boycott as part of his nation's return to negotiations.

North Korean officials said in a statement that the absence of a peace treaty is a "root cause of the hostile relations" with the U.S.

"The course of the six-party talks which witnessed repeated frustrations and failures proves that the issue can never be settled without confidence among the parties concerned," read a statement by the state-run Korean Central News Agency.

"Still today the talks remain blocked by the barrier of distrust called sanctions" against North Korea, the statement said. "The removal of the barrier of such discrimination and distrust as sanctions may soon lead to the opening of the . . . talks."

An official at the South Korean Foreign Ministry said he was suspicious of the North's motives. "We cannot say it is all good news," the official told Yonhap news service in Seoul.